Home – Home – Jornals – Flora and Vegetation of Asian Russia 2020 number 3

Sedum hybridum L. belongs to perennial herbaceous succulent-leaf plants of the Crassulaceae family. In Siberia, the species is common in the steppe zone and lower zones of mountain systems. In the southern part of forest zone, it founds fragmentarily along open slopes and cliffs with steppe vegetation. S. hybridum is a valuable medicinal, ornamental and honey plant. Due to the limited distribution in the Tomsk region, this species recommended for protection. The article presents the results of in vivo ontogeny study for S. hybridum in the southern part of forest zone in Western Siberia (within the Tomsk region). The development of individuals include 4 periods and 10 ontogenetic stages. The seeds are small, obovate, dark brown and ripen in August. In laboratory testing, seeds have high germination, which significantly related with seeds photosensitivity. Seedlings are few, appear immediately after ripening and dissemination, or in the next year spring. In the early stages of ontogenesis, the development of individuals proceeds slowly. At least 5-6 years plants pass before the first blossom. The generative period is the longest stage in the life circle of individuals. In a middle-aged generative state, individuals reach their maximal development and begin active vegetative propagation, which subsequently leads to its disintegration into new individuals. New formed clone consists of the old parental generative individual - a genet and separated particles - the ramets. Ramets formation is the results of normal or traumatic plants partitioning. They have a little bit rejuvenation (to a virgin state) and themselves are capable of repeated partitioning. Further development of ramets are similar to the development of individuals of seed origin. The transition to the postgenerative period accompanied by the gradual destruction of the perennial part of the individual with the formation of already non-viable particles. Thus, in nature, S. hybridum extremely rarely passages the complete life cycle by one seed originated individual without formation of vegetative progeny. Ontogenesis of this species is complete, complex and includes genets and ramets ontogeny.